(1) Field of the Invention
This invention relates to a traffic monitoring apparatus and, more particularly, to a traffic monitoring apparatus for detecting an abnormality in traffic by monitoring images produced by an imaging device.
(2) Description of the Related Art
In recent years intelligent transport systems (ITS), being new road systems which unite vehicle and telecommunications field and the road and traffic field, are expected to be social infrastructure which creates a market for various industries.
ITS aims at car navigation of a high order, automatic toll collection on toll roads, support for safe driving, and the like by making the best use of telecommunications technology and building humans, roads, and vehicles as a unitary system.
In order to optimally manage humans, roads, and vehicles as a system, it is necessary to always monitor the traffic situation and perform optimal control according to the situation. Therefore, traffic monitoring apparatuses for monitoring the traffic situation must be located at key points on a road to collect information.
Conventionally, the following two types of apparatuses were proposed as such a traffic monitoring apparatus.
(1) Japanese Patent Laid-Open Publication No.Hei8-116528 discloses an apparatus for detecting an accident by the noise of a vehicle crash.
(2) Japanese Patent Laid-Open Publication No.Hei10-40490 discloses an apparatus for detecting an accident by an image.
In the former method, as shown in FIG. 15, mike m1 is located at a point to be monitored to detect a power spectrum specific to a ultrasonic range occurring when vehicles V1 and V2 crash. If a plurality of mikes are located, the direction in which a crash has occurred also can be presumed to some extent on the basis of time lags between crash noises detected by these mikes.
In the latter method, as shown in FIG. 16, camera C1 is located at a point to be monitored to detect move vector MV1 of vehicle V1 and move vector MV2 of vehicle V2 from images produced. If these move vectors intersect, it will be decided that an accident has occurred.
With the former method, however, it is difficult to detect accidents, such as one resulting in injury or death, where crash noise does not occur.
Moreover, with the latter method, image processing must be performed to detect a move vector. This processing is time-consuming, so a computer with excellent throughput must be used to realize a practical processing level, resulting in a high cost. In addition, this method detects only the intersection of vectors, being an event occurring in a short time, so precision in detecting an accident is not very high. That is to say, detecting errors occur frequently.
In order to address such a problem, the present invention was made. In other words, an object of the present invention is to provide a traffic monitoring apparatus which can detect an accident resulting in injury or death and detect an accident with high precision.
In order to achieve the above object, a traffic monitoring apparatus for detecting an abnormality in traffic by monitoring images produced by an imaging device is provided. This traffic monitoring apparatus comprises image inputting means for inputting images produced by the imaging device, move vector extracting means for extracting a move vector of an object from images input from the image inputting means, parameter calculating means for calculating parameters in the case of a move vector extracted by the move vector extracting means being considered as a segment, plotting means for plotting parameters for a segment calculated by the parameter calculating means in a two-dimensional coordinate system with the parameters as its bases, and abnormality judging means for judging, in the case of parameters for a segment plotted by the plotting means having been plotted in an unusual area, that an abnormality has occurred.
The above and other objects, features and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate preferred embodiments of the present invention by way of example.